1. Field of the Invention
The present invention relates to an applicator of viscous and non-viscous material, and more particularly to a dispensing gun for applying sealants and adhesives.
2. Background Information
In the field of aircraft production and maintenance, adhesives and sealants are continuously being applied to aircraft components. Sealants are used on many of the components of an aircraft to insure that the aircraft's cabin maintains a near-standard air pressure, even at elevations as high as 60,000 feet. Sealants are also used to prevent fuel leakage from wing tanks on an aircraft.
To apply different sealant products, some form of application technology is required when producing an aircraft. For many years, applicator guns were used in the aerospace industry. An applicator gun 300, as shown in FIG. 1, uses a solid plastic tube 301 made of low-density polyethylene for holding a sealant. Each tube 301 includes a plunger surface 302, a casing 304, and a disposable cap 306. The applicator gun 300 has a metal holder 310 for holding the tube 301 against a pressure-applying assembly 314. The applicator gun 300 also has a knob 308 coupled with the pressure-applying trigger 309 on the assembly 314.
To load the tube 301 into the applicator gun 300, an operator unscrews the knob 308 and disengages the pressure applying assembly 314. The tube 301 is loaded into the metal holder 310 and the assembly 314 is reattached to the metal tube 310. The cap 306 on the tube 301 is removed and discarded to allow egress of the sealant contained in the tube 301. The nozzle 311 is attached to aid in flow control. The sealant is applied by squeezing the trigger 309, causing the assembly 314 to pressure up with compressed air against the back of the plunger surface 302, moving it forward. The movement of the plunger surface 302 forces the sealant out of the nozzle 311. Removal of the spent tube 301 is accomplished in the same manner as its installation, only in reverse.
Unfortunately, the sealant applicator gun 300 uses disposable cartridges, which are made of hard plastic material. As such, they are not easily compressible, and generate large amounts of hazardous waste, which must be disposed of at high cost. Further, the present method of using hard plastic tubes decreases productivity because of the extensive amount of time necessary to both fill the tubes and then manually swap them once one has been emptied. Finally, the size of the hard tube is not easily varied, and each tube is relatively expensive to produce. Consequently, there is a need in the art for an inexpensive and rapid device for applying sealant, which produces a minimal amount of hazardous waste.